DOC: Groupby transform should mention that parameter can be a string

[seanjedi]

• closes DOC: Docs for groupby.transform() should mention that function parameter can be a string in transform  #49961
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added type annotations to new arguments/methods/functions.
• Added an entry in the latest pandas/core/groupby/groupby.py

[rhshadrach]

@seanjedi - thanks for the PR! Can you shorten the title (there is an edit button above) - being concise is best here.

[ramvikrams]

@seanjedi can you add examples also,
For dataframegroupby you can add
grouped.transform("sum")
with it's output and similarly for SeriesGroupBy.transform()

[seanjedi]

@ramvikrams Responding to: #50029 (comment)
I believe that the docs for dataframegroupby and SeriesGroupBy transform utilizes the same location for their docs in the code, so it only requires the changes I made in that location to show up for both, as this is a template that get's used by those respective classes.
Would you want me to add what to expect for the output for this function in general? (I think it already does that?)
Or for dataframegroupby and SeriesGroupBy in particular?

Also, I have updated the code here for the example with grouped.transform("sum")
3b84281

[ramvikrams]

@ramvikrams Responding to: #50029 (comment)
I believe that the docs for dataframegroupby and SeriesGroupBy transform utilizes the same location for their docs in the code, so it only requires the changes I made in that location to show up for both, as this is a template that get's used by those respective classes.
Would you want me to add what to expect for the output for this function in general? (I think it already does that?)
Or for dataframegroupby and SeriesGroupBy in particular?

Also, I have updated the code here for the example with grouped.transform("sum")
3b84281

I think we have to change the example also for Series it must be with pd.Series

[seanjedi]

@ramvikrams is this better?
b06287e

In DataFrameGroupBy.transform it should be pd.Dataframe = grouped.transform("sum")
and in SeriesGroupBy.transform it should be pd.Series = grouped.transform("sum")

[ramvikrams]

@ramvikrams is this better?
b06287e

I think changing the example for series and then rewriting it completely because right now it's with pd.dataframe

[seanjedi]

@ramvikrams Sorry, I had to update my comment, for b06287e it should be updating the template, so that:
In DataFrameGroupBy.transform it should be pd.Dataframe = grouped.transform("sum")
and in SeriesGroupBy.transform it should be pd.Series = grouped.transform("sum")

Since %(klass)s seems to be updated in the docs to what is using it, so in DataFrameGroupBy it gets updated to Dataframe, and SeriesGroupBy it gets changed to Series

So I am a bit confused since that is what you wanted correct?
Or am I mistaking the request?
Care to elaborate a little bit more, as I am a bit confused by the ask sorry.

[ramvikrams]

I am trying to say that this example

df = pd.DataFrame({'A' : ['foo', 'bar', 'foo', 'bar',
                          'foo', 'bar'],
                   'B' : ['one', 'one', 'two', 'three',
                          'two', 'two'],
                   'C' : [1, 5, 5, 2, 5, 5],
                   'D' : [2.0, 5., 8., 1., 2., 9.]})

which is there in SeriesGroupBy.transform can you also change this it should be with pd.Series not dataframe, so can you rewrite this.

[seanjedi]

Ohh I see, I made an update here for that, hopefully, that fixes it, let me know where else I should do that change as well
f6c24f7

I see some other dataframes in the doc (IE line 467 and 484), but it is specifically saying when using transform with dataframes, so I am unsure if I should change it

[ramvikrams]

@seanjedi can you change this for the series example

ser = pd.Series(
        [390.0, 350.0, 30.0, 20.0],
        index=["Falcon", "Falcon", "Parrot", "Parrot"],
        name="Max Speed",
    )

[seanjedi]

@ramvikrams I think this should resolve the ask that you had: 207abd6
Let me know if there is something else i should change

[seanjedi]

@rhshadrach Any other changes I should make?

[rhshadrach]

This looks really good! One small request

[rhshadrach]

lgtm, ping on green.

[mroeschke]

Thanks @seanjedi

[seanjedi]

@mroeschke Thanks for merging it, and also sorry for the late reply, I am in grad school and this is finals week so I have been a bit busy today.
Glad I was able to contribute!